Some painting projects require several coats of paint over the course of several days, or possibly weeks. After a roller is used to apply paint, it must be discarded, or cleaned so that it is in good working condition for the next use. Discarding a roller after one use is expensive and wasteful. Cleaning a paint-covered roller is messy, time consuming, and generates undesirable cleaning by-products. The cleaning of wet paint rollers generates waste materials such as paint-laden water or organic solvent (generally, mineral spirits and turpentine), and paint and water or solvent-laden paper towels or rags. These cleanup materials add cost and generate waste going into the environment. Some people discard the wet roller, and use another one for the next painting. This generates multiple rollers which are discharged into the waste stream.
Cleaning a roller requires thorough rinsing with water or solvent depending on the base of the paint. If a paint roller is not cleaned completely, the remaining paint hardens on the roller, and it hinders or destroys the roller's ability to apply paint properly on its next use.
There are some references in painters' tips and handyman articles on the internet, for example, about rolling or folding up wet paint rollers in aluminum foil, in an attempt to preserve the water or solvent in the paint on the roller. There are many ways to wrap the roller up in foil, and these many ways are not air tight and do not significantly inhibit transfer of air and other vapors into and out of the foil. Thus, the water or solvent escapes, and the paint hardens on the roller. Paint can also leak out, causing a mess. Some paints can also corrode bare foil, creating holes, thereby allowing leakage as well.
Other references are found that recommend placing a wet paint roller in a polyethylene bag, and wrapping it up. Again, if an air-tight or leak-resistant seal is not made, water and solvent can leak out. Polyethylene, commonly used in sandwich bags, trash bags, grocery bags, and bread bags, provides a moderate barrier to water and moisture, but virtually no barrier to most organic solvents. Oil and solvent-based paints quickly loose their solvent through the polyethylene, and the paint hardens on the roller.
There are several brands of rigid plastic thermoformed clamshells being marketed to store wet rollers on roller frames. The roller frame/wet roller assembly is placed on one half of the clamshell, and the clamshell is then folded over and kept closed with a mechanical interlocking feature. They rely on a friction-fit mechanical interlocking feature, such as lugs, around their perimeter to remain closed. There is a hole in the clamshell which allows the roller frame's handle rod to extend beyond the clamshell. One problem with rigid clamshells is that roller frames have different shapes, and some do not conform to the rigid clamshell's recessed areas. The result is that the user can not make the friction fit closure on some types of roller frames, because the roller frame interferes with the alignment of the friction-fit edges. The result is a partially closed clamshell that does not contain the water or chemical solvent in the paint. The paint is also free to leak out, causing a mess. The interlocking friction-fit method of closure, even when functioning correctly, is not vapor-tight, and the water and/or solvents leak out in a short period of time (1-2 days), allowing the paint on the roller to harden. Leakage also occurs around the hole that allows the roller frame to extend beyond the clamshell. The clamshell is made from hard plastic, and it does not conform (come into complete intimate contact) to the roller frame. Roller frames have handle rods that vary in size. Smaller diameter handle rods allow more leakage where they pass through the larger diameter hole in the clamshell. If the user wants to store the roller off the frame in a clamshell, the open hole provides a large passage through which moisture and/or solvent can escape quickly. Some commercial clamshells include a plug for the hole, some do not. The plugs provided are of the same hard plastic, and do not form an air-tight seal.
There are several rigid plastic and rigid metal containers that have met with little or no apparent commercial success. They typically teach using a rigid container to store a wet paint roller, and then eventually the container itself needs to be cleaned afterwards. By virtue of their sturdy design and higher cost, rigid containers are not generally viewed as disposable. The rigid container must be filled with water or solvent, and the paint-laden roller is to be submersed into it. This adds further mess and complexity, in that the water and solvent must be removed from the roller before it will evenly hold and distribute paint.
There remains a need for an inexpensive, disposable product to temporarily store a wet paint roller between uses, to facilitate the saving of time, money, and cleaning supplies, that conforms to all roller frame configurations, that provides a sufficiently vapor-tight or vapor-resistant seal, and that also works for roller storage on or off the roller frame.